Colin Kaepernick is expected to be under center Sunday when the 49ers look to extend their winning streak to five games against the New Orleans Saints.

Smith has been demoted to second-team reps in practice by head coach Jim Harbaugh, who was left impressed by Kaepernick's performance in Monday's 32-7 drubbing of the Chicago Bears.

Kaepernick's second NFL start will pit him against one of the best quarterbacks to ever play the game. Drew Brees leads a Saints team that has reeled off three straight victories and is 5-1 since opening the year with four straight losses.

As expected, Brees has been the catalyst - he torched the Oakland Raiders for three scores in a Week 11 victory and has thrown multiple touchdown passes in all but one game this season. He'll be in tough against a San Francisco defense allowing the second-fewest passing yards in the league.

The 49ers:

As Smith sat recovering from a concussion, Kaepernick staked his claim to the starting role with 243 passing yards and two touchdowns against Chicago's vaunted defense. Kaepernick was given a ringing post-game endorsement by tight end Vernon Davis, who finished with six catches for 83 yards and a score. "I felt like somebody took the handcuffs off me," said Davis, who had amassed just nine catches for 101 yards in his previous four contests - all with Smith at the helm.

The Saints:

While New Orleans' offense continues to roll over the opposition, the defense has made quiet strides during the team's current winning streak. The Saints kept Oakland at bay in a 38-17 victory on Sunday and has surrendered an average of 19 points over its last three games. Running back Darren Sproles has been participating in practice and is expected to return after missing the last three weeks with a broken hand. Sproles will be a popular option for Brees in what becomes a muddled backfield.